1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* Kernel module to match one of a list of TCP/UDP(-Lite)/SCTP/DCCP ports: |
3 | ports are in the same place so we can treat them as equal. */ |
4 | |
5 | /* (C) 1999-2001 Paul `Rusty' Russell |
6 | * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org> |
7 | */ |
8 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
9 | #include <linux/module.h> |
10 | #include <linux/types.h> |
11 | #include <linux/udp.h> |
12 | #include <linux/skbuff.h> |
13 | #include <linux/in.h> |
14 | |
15 | #include <linux/netfilter/xt_multiport.h> |
16 | #include <linux/netfilter/x_tables.h> |
17 | #include <linux/netfilter_ipv4/ip_tables.h> |
18 | #include <linux/netfilter_ipv6/ip6_tables.h> |
19 | |
20 | MODULE_LICENSE("GPL" ); |
21 | MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>" ); |
22 | MODULE_DESCRIPTION("Xtables: multiple port matching for TCP, UDP, UDP-Lite, SCTP and DCCP" ); |
23 | MODULE_ALIAS("ipt_multiport" ); |
24 | MODULE_ALIAS("ip6t_multiport" ); |
25 | |
26 | /* Returns 1 if the port is matched by the test, 0 otherwise. */ |
27 | static inline bool |
28 | ports_match_v1(const struct xt_multiport_v1 *minfo, |
29 | u_int16_t src, u_int16_t dst) |
30 | { |
31 | unsigned int i; |
32 | u_int16_t s, e; |
33 | |
34 | for (i = 0; i < minfo->count; i++) { |
35 | s = minfo->ports[i]; |
36 | |
37 | if (minfo->pflags[i]) { |
38 | /* range port matching */ |
39 | e = minfo->ports[++i]; |
40 | pr_debug("src or dst matches with %d-%d?\n" , s, e); |
41 | |
42 | switch (minfo->flags) { |
43 | case XT_MULTIPORT_SOURCE: |
44 | if (src >= s && src <= e) |
45 | return true ^ minfo->invert; |
46 | break; |
47 | case XT_MULTIPORT_DESTINATION: |
48 | if (dst >= s && dst <= e) |
49 | return true ^ minfo->invert; |
50 | break; |
51 | case XT_MULTIPORT_EITHER: |
52 | if ((dst >= s && dst <= e) || |
53 | (src >= s && src <= e)) |
54 | return true ^ minfo->invert; |
55 | break; |
56 | default: |
57 | break; |
58 | } |
59 | } else { |
60 | /* exact port matching */ |
61 | pr_debug("src or dst matches with %d?\n" , s); |
62 | |
63 | switch (minfo->flags) { |
64 | case XT_MULTIPORT_SOURCE: |
65 | if (src == s) |
66 | return true ^ minfo->invert; |
67 | break; |
68 | case XT_MULTIPORT_DESTINATION: |
69 | if (dst == s) |
70 | return true ^ minfo->invert; |
71 | break; |
72 | case XT_MULTIPORT_EITHER: |
73 | if (src == s || dst == s) |
74 | return true ^ minfo->invert; |
75 | break; |
76 | default: |
77 | break; |
78 | } |
79 | } |
80 | } |
81 | |
82 | return minfo->invert; |
83 | } |
84 | |
85 | static bool |
86 | multiport_mt(const struct sk_buff *skb, struct xt_action_param *par) |
87 | { |
88 | const __be16 *pptr; |
89 | __be16 _ports[2]; |
90 | const struct xt_multiport_v1 *multiinfo = par->matchinfo; |
91 | |
92 | if (par->fragoff != 0) |
93 | return false; |
94 | |
95 | pptr = skb_header_pointer(skb, offset: par->thoff, len: sizeof(_ports), buffer: _ports); |
96 | if (pptr == NULL) { |
97 | /* We've been asked to examine this packet, and we |
98 | * can't. Hence, no choice but to drop. |
99 | */ |
100 | pr_debug("Dropping evil offset=0 tinygram.\n" ); |
101 | par->hotdrop = true; |
102 | return false; |
103 | } |
104 | |
105 | return ports_match_v1(minfo: multiinfo, ntohs(pptr[0]), ntohs(pptr[1])); |
106 | } |
107 | |
108 | static inline bool |
109 | check(u_int16_t proto, |
110 | u_int8_t ip_invflags, |
111 | u_int8_t match_flags, |
112 | u_int8_t count) |
113 | { |
114 | /* Must specify supported protocol, no unknown flags or bad count */ |
115 | return (proto == IPPROTO_TCP || proto == IPPROTO_UDP |
116 | || proto == IPPROTO_UDPLITE |
117 | || proto == IPPROTO_SCTP || proto == IPPROTO_DCCP) |
118 | && !(ip_invflags & XT_INV_PROTO) |
119 | && (match_flags == XT_MULTIPORT_SOURCE |
120 | || match_flags == XT_MULTIPORT_DESTINATION |
121 | || match_flags == XT_MULTIPORT_EITHER) |
122 | && count <= XT_MULTI_PORTS; |
123 | } |
124 | |
125 | static int multiport_mt_check(const struct xt_mtchk_param *par) |
126 | { |
127 | const struct ipt_ip *ip = par->entryinfo; |
128 | const struct xt_multiport_v1 *multiinfo = par->matchinfo; |
129 | |
130 | return check(proto: ip->proto, ip_invflags: ip->invflags, match_flags: multiinfo->flags, |
131 | count: multiinfo->count) ? 0 : -EINVAL; |
132 | } |
133 | |
134 | static int multiport_mt6_check(const struct xt_mtchk_param *par) |
135 | { |
136 | const struct ip6t_ip6 *ip = par->entryinfo; |
137 | const struct xt_multiport_v1 *multiinfo = par->matchinfo; |
138 | |
139 | return check(proto: ip->proto, ip_invflags: ip->invflags, match_flags: multiinfo->flags, |
140 | count: multiinfo->count) ? 0 : -EINVAL; |
141 | } |
142 | |
143 | static struct xt_match multiport_mt_reg[] __read_mostly = { |
144 | { |
145 | .name = "multiport" , |
146 | .family = NFPROTO_IPV4, |
147 | .revision = 1, |
148 | .checkentry = multiport_mt_check, |
149 | .match = multiport_mt, |
150 | .matchsize = sizeof(struct xt_multiport_v1), |
151 | .me = THIS_MODULE, |
152 | }, |
153 | { |
154 | .name = "multiport" , |
155 | .family = NFPROTO_IPV6, |
156 | .revision = 1, |
157 | .checkentry = multiport_mt6_check, |
158 | .match = multiport_mt, |
159 | .matchsize = sizeof(struct xt_multiport_v1), |
160 | .me = THIS_MODULE, |
161 | }, |
162 | }; |
163 | |
164 | static int __init multiport_mt_init(void) |
165 | { |
166 | return xt_register_matches(match: multiport_mt_reg, |
167 | ARRAY_SIZE(multiport_mt_reg)); |
168 | } |
169 | |
170 | static void __exit multiport_mt_exit(void) |
171 | { |
172 | xt_unregister_matches(match: multiport_mt_reg, ARRAY_SIZE(multiport_mt_reg)); |
173 | } |
174 | |
175 | module_init(multiport_mt_init); |
176 | module_exit(multiport_mt_exit); |
177 | |